Exclusion Errors in Pressure Chamber Estimates of Leaf Water Potential

1975 ◽  
Vol 39 (4) ◽  
pp. 915-920 ◽  
Author(s):  
B. D. MILLAR ◽  
G. K. HANSEN
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Pressure Chamber ◽  
Leaf Water

Evaluation of the hydraulic press for measurement of leaf water potentials in cassava

1983 ◽  
Vol 101 (2) ◽  
pp. 407-410 ◽  
Author(s):  
J. A. Palta
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Hydraulic Press ◽  
Pressure Chamber ◽  
Leaf Water ◽  
Moisture Loss ◽  
Total Leaf Area ◽  
Water Potentials ◽  
Wide Range ◽  
Poor Relationship

SUMMARYIn the application of the Scholander pressure chamber technique to cassava water relations studies, the leaf water potential measured on central lobules was initially compared with that measured on entire leaves (including petiole). Measurements made using both a Campbell-Brewster hydraulic press and a pressure chamber of the leaf water potential in six different cassava clones were also compared. Although the central lobules showed a greater sensitivity to moisture loss after sampling than entire leaves, their leaf water potential was in close agreement with those measured on the entire leaves (r3 = 0·96). Therefore, for routine and field estimates in cassava, measurements made on the central lobules may be used to avoid the large reduction in total leaf area. The Campbell-Brewster hydraulic press satisfactorily estimated leaf water potential in M.Col. 1684 clone, which had the longest and narrowest lobules, but in other clones the leaf water potential was overestimated at high leaf potential (> -12·5) and underestimated at low water potentials (< -12·5). Over a wide range of leaf water potentials, a poor relationship between leaf water potentials estimated with hydraulic press and with the pressure chamber was observed for cassava because press estimates are influenced by lobule length and lobule width.

scholarly journals Vine water deficit : among the 3 applications of pressure chamber, stem water potential is the most sensitive indicator

OENO One ◽  
2000 ◽  
Vol 34 (4) ◽  
pp. 169
Author(s):  
Xavier Choné ◽  
Olivier Trégoat ◽  
Cornelis Van Leeuwen ◽  
Denis Dubourdieu
Keyword(s):  
Water Potential ◽  
Water Deficit ◽  
Leaf Water Potential ◽  
Water Status ◽  
Pressure Chamber ◽  
Leaf Water ◽  
Sensitive Indicator ◽  
Stem Water Potential ◽  
Water Deficits ◽  
Stem Water

<p style="text-align: justify;">Vine water status is an important factor in grape quality. High tannin and anthocyanin content in red grape berries are related to moderate vine water deficits. Hence, a simple and sensitive indicator is required to determine vine water status and especially water constraint. Pressure chamber allows a quick and easy to practice determination of water status in the vineyard. Three applications of pressure chamber are known: predawn leaf water potential (ΨB), leaf water potential (ΨF) and stem water potential (ΨT). Only ΨB and ΨF are widely used on vines. In this survey ΨB, ΨF, ΨT and transpiration flow were measured on mature leaves to determine non-irrigated vine water status in field grown vines during the growing season. In California as well as in France, stem Ψ was the most discriminating indicator for both moderate and severe water deficits. In every plot surveyed ΨT was much better correlated to leaf transpiration than ΨF. Moreover, ΨT revealed nascent water deficit earlier than ΨB did. Among the three application of pressure chamber, ΨT was the only one to indicate short term water deficit after a rainfall. Hence, ΨT appears to be a useful indicator for grapevine management in both non-irrigated and irrigated vineyards.</p>

Errors Arising From Rapid Water Loss in the Measurement of Leaf Water Potential by the Pressure Chamber Technique

1980 ◽  
Vol 7 (5) ◽  
pp. 527 ◽  
Author(s):  
NC Turner ◽  
MJ Long
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Water Loss ◽  
Water Retention ◽  
Pressure Chamber ◽  
Leaf Water ◽  
Diurnal Changes ◽  
Water Potentials ◽  
Retention Characteristics ◽  
Flow Through

In rapidly transpiring leaves, the water potentials of uncovered leaves measured in a pressure chamber were 0.2-0.7 MPa lower than the water potentials of leaves that were covered with a plastic sheath from just prior to their excision to the completion of the measurement. The error in the water potential of uncovered leaves arose from rapid water loss in the first 30 s after excision. The degree to which the water potentials were lowered depended on the rate of transpiration, the leaf water potential at the time of excision, the species, and whether the plants were grown in the glasshouse or field. It is suggested that the variation between species and between glasshouse-grown and field-grown plants arises from differences in water retention characteristics of plant tissue as well as to differences in the rates of transpiration at excision. The size of the error induced by the rapid water loss on diurnal changes in leaf water potential is demonstrated and the effect of the error in the calculation of turgor potentials and in the resistances to water flow through the plant is discussed.

Bias in pressure chamber measurements of leaf water potential

1982 ◽  
Vol 27 (3-4) ◽  
pp. 257-263 ◽  
Author(s):  
J.E. Leach ◽  
T. Woodhead ◽  
W. Day
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Pressure Chamber ◽  
Leaf Water ◽  
Chamber Measurements

scholarly journals Grapevine leaf water potential based upon near infrared spectroscopy

2009 ◽  
Vol 66 (3) ◽  
pp. 287-292 ◽  
Author(s):  
Antonio Odair Santos ◽  
Oren Kaye
Keyword(s):  
Infrared Spectroscopy ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Water Status ◽  
Correlation Coefficients ◽  
Pressure Chamber ◽  
Leaf Water ◽  
Intensive Sampling

Leaf water potential is a measure commonly used to describe crop water status and water stress dynamics. The established method for determining leaf water potential using a pressure chamber is cumbersome and subject to operator error as well as time/temperature limitations. These limitations prohibit the intensive sampling required to support proactive water management of commercial crops, including vineyards. Particular for grapevines there is need for faster, more precise and more reliable tools for determining leaf water potential in the field. Portable Near-infrared spectroscopy and multivariate data analysis were applied for the modeling and prediction of leaf water potential in grapevines. For field-grown wine grapes the most significant and intensive leaf absorptions occurs in the region from 1440 to 1950 nm and again beyond 2,200 nm. Multivariate analysis of these spectra, referenced against pressure chamber measurements as a standard, showed correlation coefficients from 0.87 to 0.95 clearly demonstrated that this technology can provide a fast and reasonable assessment of leaf water potential in the field.

Evaluation of the pressure chamber technique for measurement of leaf water potential in cassava (Manihot species)

1978 ◽  
Vol 56 (14) ◽  
pp. 1638-1641 ◽  
Author(s):  
I. F. Ike ◽  
G. W. Thurtell ◽  
K. R. Stevenson
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Pressure Chamber ◽  
Leaf Water ◽  
Dew Point ◽  
Manihot Esculenta Crantz ◽  
Osmotic Potentials ◽  
Chamber Technique ◽  
Cassava Varieties

The pressure chamber technique was evaluated as a method for estimating leaf water potential in cassava (Manihot esculenta Crantz). Xylem pressure potentials (ψP) measured with the pressure chamber were compared with leaf water potential (ψL) obtained for the same leaf with the in situ dew-point hygrometer.In both cassava varieties studied, ψL and ψP were linearly related (r2 = 0.87 and 0.98 for CMC9 and CMC40 respectively). The length of petiole exposed outside the chamber affects the relation between ψL and ψP and should be kept at between 1 and 3 cm for better agreement. In CMC40, ψP was consistently lower (drier) than ψL by about 1.0 bar (1 bar = 100 kPa) in the entire range of water potential studied, but was not the case in CMC9. The reason for this difference is unclear but may be due to a filling of tissues other than xylem tissues (Boyer 1967) during the measurement of ψP in CMC40. Average xylem osmotic potentials (ψS) were low (−1.0 ± 0.2 bars and −1.0 ± 0.4 bars for CMC9 and CMC40 respectively). It is, therefore, unnecessary to correct for ψS when using the pressure chamber to estimate leaf water potentials in cassava.

scholarly journals Comparisons of Leaf Water Potential and Xylem Water Potential in tomato Plants

1970 ◽  
Vol 23 (2) ◽  
pp. 485 ◽  
Author(s):  
HD Barrs ◽  
B Freeman ◽  
J Blackwell ◽  
RD Ceccato
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Pressure Chamber ◽  
Leaf Water ◽  
Present Communication ◽  
Pressure Potential ◽  
Xylem Water Potential ◽  
Tomato Plants ◽  
Water Potentials ◽  
Xylem Pressure Potential

The rapidity and convenience of the pressure chamber technique for estimating leaf water potentials, especially under field conditions, has been remarked (Boyer 1967; Kaufmann 1968a, 1968b) and demonstrated (Klepper and Ceccato 1969). However, Kaufmann (1968a) showed that it is necessary to exercise caution .in using measurements made with the pressure chamber as direct estimates of leaf water potential. Instead, he recommended that calibration curves should be drawn up for each species, relating measurements of xylem pressure potential obtained with this technique to corresponding known leaf water potentials. The present communication reports such a relation for tomato leaves, which have not previously been studied in this way. Plant age is shown to affect the relation.

scholarly journals Measuring Leaf-water Potential in Chickpea with a Pressure Chamber

1979 ◽  
Vol 15 (4) ◽  
pp. 377-383 ◽  
Author(s):  
M. V. K. Sivakumar ◽  
S. M. Virmani
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Leaf Water Potential ◽  
Water Status ◽  
Pressure Chamber ◽  
Leaf Water ◽  
Leaf Water Status ◽  
Irrigated Crops ◽  
Different Depths ◽  
First Time

SUMMARYThe pressure-chamber technique has been used for the first time to measure leaf-water potentials in chickpea under field conditions. Available soil-water contents at different depths for irrigated and non-irrigated crops are presented along with the diurnal variation in leaf-water status, to show that pressure-chamber measurements correspond closely with available soil water. Leaf-water potential has also shown differences in leaf-water status among different cultivars. The rapidity and ease with which measurements can be made in the field make the technique suitable for quick measurements of leaf-water status for chickpea.

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